Kodak type A safelight conundrum

[David]

I'm just about finished making my new darkroom. I have two Kodak type A safelights (bullet type) with the screw in style base (Edison type base). The darkroom has been newly wired with the appropriate new receptacles. If I screw a bulb into the receptacle it works as you would expect. When I screw in the safelight it does not work. I've tried slightly extending the centre electrode of the receptacle to make sure that it is making contact with the male side of the safelight and have done the same with the female side inside of the light housing in order to make certain that adequate contact is being made with the bulb. The problem occurs with both lights.

Thanks in advance for your thoughts and suggestions.

 

[gone]

You have some bad bullet receptacles I would venture to say David. I have one of those, and it works just like a regular big light bulb. This may sound dumb, but you have unscrewed the fronts to make sure they have bulbs inside, right?

 

[bdial]

Do you have access to a multimeter or other continuity tester? That might help isolate what the exact problem is.

In theory, there isn't much to go wrong with the lights you're describing, it therefore seems odd that you have two that don't work. Have you tried testing them in other light receptacles?

 

[aoresteen]

Or the bulbs are burnt out. Try a new 15 watt bulb.

 

[Photo Engineer]

Some of these safelights have a small thumb switch on the cord to turn the bulb on and off. Could yours be one of them, and could the switch be off?

PE

 

[frobozz]

I think he's got the kind where the safelight body itself screws directly into the receptacle (which I guess assumes that the receptacle has a switch to control it somewhere, like if you were replacing an overhead light with a pull chain with this safelight.)

Duncan

 

[fotch]

It may be the new receptacles. It regular bulbs work in them, and the safelights work in other receptacles, then the receptacles are the problem. Maybe imported lower grade receptacles? You can then maybe get an extension receptacles at the hardware store, the type that converts the light bulb receptacle to one with plugs and light bulb.

 

[David]

Thank you for your replies. Yes, I made sure that the bulbs I placed in the safelight housing were working lights, in fact they worked just fine when screwed into the receptacles on their own. The receptacles are new, good quality units. There are no switches as these lights screw directly into the socketed receptacle. These receptacles are indeed connected to a switch, all of which works except with the safelights. I can only assume a lack of connection somewhere inasmuch as the bare globes work just fine in the system. By a lack of connection I imagine a physical shortness between the centre electrodes and the pointed end of the bulb. It;s a bit frustrating as I am awaiting (safe)light from these in order to use the darkroom.

Also, it isn't possible to check these safelights in other receptacles since all other receptacles are designed for bayonet type bulbs. Again, thanks for your thoughts. Hopefully there's a solution somewhere.

Cheers,
David

 

[Photo Engineer]

David can you send a photo in a post?

PE

 

[DWThomas]

This is far fetched, but I remember as a kid hearing a tale that early in the history of electric bulbs there was an international conference to standardize them. The story (probably an urban legend) was that after much haggling, other parts of the world agreed to use the USA thread diameter and pitch -- but they then made their sockets one thread deeper so US bulbs wouldn't work in them (but theirs would work in the US. ) So anyway, is the length of the thread portion of the bulbs that work directly in a socket the same length as the thread on the safelight? If the bulb thread is longer, maybe the safelight bottoms out mechanically before electrical contact is made.

If that is the case, it could probably be fixed by soldering a short length of brass tubing on the center contact on the outside end of the safelight.

 

[Roger Cole]

Have you checked the safelights in OTHER receptacles? Could be they're just bad?

 

[Rick A]

(there was a url link here which no longer exists)

 

[David]

I'll make some photos this evening and then post them. Thanks for the referral to the thread on APUG. I saw that before posting my thread and unfortunately that article deals with the Type A safelight that has a cord rather than a straight pass screw in head on the safelight.

 

[richard ide]

Some problems I have run across:
Check for corrosion on the bottom contact and scrape with a screwdriver.
Some contacts are folded; bend up.
Have used soldering gun to enlarge blob of solder on bottom so it makes contact.

 

[George Nova Scotia]

I decided to head into the darkroom and have a look at mine. Turned and turned and turned and it didn't come out of the socket, finally realized that metal shell was just spinning around, the Bakelite portion just staying put. Any chance you have reverse going on, the shell starts to spin before the contacts make it to the bottom of the socket?

 

[Photo Engineer]

Either way, it would twist the wires until they broke.

PE

 

[randyB]

As Richaed said, check for corrosion on the contacts. Over time a film can build up on the contacts that prevents the flow of electrons. I usually take a small piece of sandpaper and clean any metal contact till bright. Do the same with the base of the bulb.

 

[David]

Hi everyone, Thanks for your patience as I finally get back to this item. I ended up thinking outside of the box and solved the problem. In short, I removed the 'gender changer' screw in device (the item that screws into the receptacle and into which the light bulb screws. I placed the body of the safelight over the properly insulated ceiling receptacle and then screwed essentially a large nut that was part of the receptacle back onto the receptacle thus holding the safelight housing tight. I am now able to screw the bulb directly into the receptacle, there is no light leakage from the top, the metal safelight housing is insulated from electrical activity and, as they say here, Bob's your uncle.

Thank you for your good thoughts and for sharing them. I hope the description wasn't too obtuse.